Artificial denture



R. M. WITHYCOMBE ARTIFICIAL DENTURE Filed June 30. 1924 Patented Dec. 18, 1928.

UNITED .STATES PATENT oFFlcE. Y

ROBERT MORSE WITHYCOMBE, OF SYDNEY, NEW SOUTH WALES, AUSTRALIA.

ARTIFICIAL DENTURE Application filed June 30, 1924. Serial No. 723,315.

This invention relates to artificial dentures and to a process for making the same.

Broadly, the principle of the invention is carried out by heating or otherwise treating a plate of vulcanite or like substances in a mold, the latter being formed at least in part of a substance having the property of entering into, impregna-ting, or uniting with the contacting surface material of the vul canite by a process similar to that of cementation, or case-hardening in metallurgy, so that the denture acquires in the course of the process, an integral surface layer gradually merging from a surface having characteristics imparted to it by the absorption or impregnation of the substance of the mold in maximum degree, and progressively disappearing in the deeper parts of said layer, which substance is chosen with a view to giving the denture those desirable qualities which constitute a patentable improvement over what has previously been known.

In the illustrative embodiment of the invention, which constitutes the subject-matter of the following description, I have chosen to make at least that part of the mold engaging those portions of the vulcanite which will co-act with the mouth tissues, of a composition of matter including certain proportions of copper oxide and sulphur, the same being the subject matter of my co1`npanion application Serial No. 722,830 filed June 27, 1924, PatentNo. 1,598,668, dated September 7 1926.

This mold or model may be cast from the usual wax or resinous impression, or from plaster by running in the composition of matter when in molten state.

As has been pointed out in my said companion application, this composition of matter is superior to the plaster of Paris ordinarily used for the model in that it is extremely fluid when cast, therefore filling the minutest interstices in the impression, and that it is non-porous, having a thoroughly impervious and smooth surface which is perpetuated in the vulcanite denture making the latter more satisfactory from a hygienic standpoint than a denture made from a plaster model. Said companion application mentions also other advantages possessed by my novel composition of matter which it does not seem necessary here to enumerate.

In carrying out the process of the present invention, reference may be had` to the aecompanying drawing in which Figure 1 shows, in perspective, the model for making a palatal denture cast from said novel com-` position of matter and embedded inthe usual way in the lower half of the flask.

Figures 2 is a perspective Vview of theV finished denture.

An illustration of the upper half of the mould, between which, and the lower half the denture is vulcanized, is not considered necessary as this part of the model may be made in the usual manner out of plaster.

When the contents of the flask l are subjected to heat and pressure a certain portion of the substance of that model 2 made from the mixture of copper oxide and sulphur is absorbed by the contacting surface of the vulcanite in a way that is not fully understood. Nor is it definitely known whether the change is purely physical, chemical, or both. The re-action effects a decided physical change in the outer surface 3, of the denture 4, it becoming hard, dense, and resilient so that a much thinner plate can be made than formerly, with superior esay strength and resiliency and therefore less risk of breakage. The surface thus formed is not to lbe confused with a mere coating, for it is an inseparable, unitary, integral part of the denture, exhibiting no pla-ne of separation. Notwithstanding this, a perfect plane of cleavage is preserved between the model and that part of the substance thereof which is incorporated with the vulcanite so that the model may be broken away from the denture as easily as plaster, in releasing the denture.

The denture made according to the above process may be worn advantageously with the transmuted surface in direct contact withthe mouth tissues, as the copper content of the impregnated vulcanite is inherently gerinicidal, but as the impregnated surface is electrically conductive the denture lends itself readily to a processs of electroplating and may have that surface thereof which comes into Contact with the mouth tissues coated withv metal in the electrolytic bath.

Although, for the purpose of practical disclosure, the process has been described in the making of a vulcanite denture, it is equally applicable to the treatment' of rubher, gum, or like non-conductive substances to give them an electrically conductive sur face which can be directly electro-plated.

Having described my invention what I claim as new and desire to secure by Letters c tissue contacting;r surface of a material superior to vuleanite in hardness and resiliency and having inherent germieidal properties, which material progressively changes to a state of homogeneity with the vulcaniteoi. the plate in the deeper parts ot snifl layer.

3.The process of milking a vulcanized denture which consists in placing vuleanite or the like in a mold, a part of which has :i mixture of copper oxide und sulphur in at least the surface thereof, vulennizinglr said vuleanite while in contnet with said copper containing surface, thereby producingr a transmutation in the contacting surface portion of said vuleanite.

In testimony whereof I have hereunto set my hand.

R. MORSE WITHYCOB'IBE. 

